public static int GetIntermediateAddress(int offset, bool resolve)
{
int bank, directPage, operand, programCounter;
int opcode = Data.GetROMByte(offset);
AddressMode mode = GetAddressMode(offset);
switch (mode)
{
case AddressMode.DIRECT_PAGE:
case AddressMode.DIRECT_PAGE_X_INDEX:
case AddressMode.DIRECT_PAGE_Y_INDEX:
case AddressMode.DIRECT_PAGE_INDIRECT:
case AddressMode.DIRECT_PAGE_X_INDEX_INDIRECT:
case AddressMode.DIRECT_PAGE_INDIRECT_Y_INDEX:
case AddressMode.DIRECT_PAGE_LONG_INDIRECT:
case AddressMode.DIRECT_PAGE_LONG_INDIRECT_Y_INDEX:
if (resolve)
{
directPage = Data.GetDirectPage(offset);
operand = Data.GetROMByte(offset + 1);
return((directPage + operand) & 0xFFFF);
}
else
{
goto case AddressMode.DIRECT_PAGE_S_INDEX;
}
case AddressMode.DIRECT_PAGE_S_INDEX:
case AddressMode.DIRECT_PAGE_S_INDEX_INDIRECT_Y_INDEX:
return(Data.GetROMByte(offset + 1));
case AddressMode.ADDRESS:
case AddressMode.ADDRESS_X_INDEX:
case AddressMode.ADDRESS_Y_INDEX:
case AddressMode.ADDRESS_X_INDEX_INDIRECT:
bank = (opcode == 0x20 || opcode == 0x4C || opcode == 0x7C || opcode == 0xFC) ?
Util.ConvertPCtoSNES(offset) >> 16 :
Data.GetDataBank(offset);
operand = Util.GetROMWord(offset + 1);
return((bank << 16) | operand);
case AddressMode.ADDRESS_INDIRECT:
case AddressMode.ADDRESS_LONG_INDIRECT:
operand = Util.GetROMWord(offset + 1);
return(operand);
case AddressMode.LONG:
case AddressMode.LONG_X_INDEX:
operand = Util.GetROMLong(offset + 1);
return(operand);
case AddressMode.RELATIVE_8:
programCounter = Util.ConvertPCtoSNES(offset + 2);
bank = programCounter >> 16;
offset = (sbyte)Data.GetROMByte(offset + 1);
return((bank << 16) | ((programCounter + offset) & 0xFFFF));
case AddressMode.RELATIVE_16:
programCounter = Util.ConvertPCtoSNES(offset + 3);
bank = programCounter >> 16;
offset = (short)Util.GetROMWord(offset + 1);
return((bank << 16) | ((programCounter + offset) & 0xFFFF));
}
return(-1);
}
public static int Step(int offset, bool branch, bool force, int prevOffset)
{
int opcode = Data.GetROMByte(offset);
int prevDirectPage = Data.GetDirectPage(offset);
int prevDataBank = Data.GetDataBank(offset);
bool prevX = Data.GetXFlag(offset), prevM = Data.GetMFlag(offset);
while (prevOffset >= 0 && Data.GetFlag(prevOffset) == Data.FlagType.Operand)
{
prevOffset--;
}
if (prevOffset >= 0 && Data.GetFlag(prevOffset) == Data.FlagType.Opcode)
{
prevDirectPage = Data.GetDirectPage(prevOffset);
prevDataBank = Data.GetDataBank(prevOffset);
prevX = Data.GetXFlag(prevOffset);
prevM = Data.GetMFlag(prevOffset);
}
if (opcode == 0xC2 || opcode == 0xE2) // REP SEP
{
prevX = (Data.GetROMByte(offset + 1) & 0x10) != 0 ? opcode == 0xE2 : prevX;
prevM = (Data.GetROMByte(offset + 1) & 0x20) != 0 ? opcode == 0xE2 : prevM;
}
// set first byte first, so the instruction length is correct
Data.SetFlag(offset, Data.FlagType.Opcode);
Data.SetDataBank(offset, prevDataBank);
Data.SetDirectPage(offset, prevDirectPage);
Data.SetXFlag(offset, prevX);
Data.SetMFlag(offset, prevM);
int length = GetInstructionLength(offset);
for (int i = 1; i < length; i++)
{
Data.SetFlag(offset + i, Data.FlagType.Operand);
Data.SetDataBank(offset + i, prevDataBank);
Data.SetDirectPage(offset + i, prevDirectPage);
Data.SetXFlag(offset + i, prevX);
Data.SetMFlag(offset + i, prevM);
}
MarkInOutPoints(offset);
int nextOffset = offset + length;
if (!force && (opcode == 0x4C || opcode == 0x5C || opcode == 0x80 || opcode == 0x82 || // JMP JML BRA BRL
(branch && (opcode == 0x10 || opcode == 0x30 || opcode == 0x50 || // BPL BMI BVC
opcode == 0x70 || opcode == 0x90 || opcode == 0xB0 || opcode == 0xD0 || // BVS BCC BCS BNE
opcode == 0xF0 || opcode == 0x20 || opcode == 0x22)))) // BEQ JSR JSL
{
int iaNextOffsetPC = Util.ConvertSNEStoPC(Util.GetIntermediateAddress(offset, true));
if (iaNextOffsetPC >= 0)
{
nextOffset = iaNextOffsetPC;
}
}
return(nextOffset);
}